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What color is graphite?

Graphite has a hardness of 1 to 2 on the Mohs scale and has a streak color of black. It features a crystalline structure and a perfect basal cleavage, meaning that it breaks in plate-like pieces with hexagonal edges. Graphite is used industrially as a lubricant and in manufacturing batteries, steel and brake linings among other applications. It is also used in manufacturing synthetic carbon-based plastics.

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How many penguins are left in the world?

There are 17 different penguin species. With an estimated 9 million breeding pairs, the most populous species is the macaroni penguin, which lives on islands in the Subantarctic and on the Antarctic peninsula. Galapagos penguins, which live on the Galapagos islands off the coast of Ecuador, have the lowest population at about 1,200 mature individuals.\nMany species of penguin are listed as threatened or endangered by the Endangered Species Act, but some species, such as the Adelie penguin, are increasing their numbers.

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What is acceleration?

Acceleration always requires a force be applied to the accelerating object or substance. The tendency of any object is to maintain its current velocity, a property known as inertia. The resistance of any object to acceleration is known as its inertial mass. Regardless of this inertial mass, however, any net force applied to an object produces an acceleration, although it may be so small as to be undetectable.\nAcceleration really has two related but quite different meanings in casual and scientific use. When many people speak of acceleration, they just mean an increase in speed, while a decrea..

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List all the phyla that show cephalization?

Vertebrates include such animals as placental mammals, marsupials, birds, reptiles, amphibians and most fish.\nMost animals are arthropoda. These include insects, spiders, millipedes and centipedes, and crustaceans such as shrimp and lobster. All of them have a segmented exoskeleton and jointed legs. Many live out of water, while some are aquatic. In others the larval stage is aquatic, while the adult is terrestrial. This life cycle can be seen in dragonflies and damselflies.\nPlatyhelminthes include flatworms. They're the simplest type of animal that show bilateral symmetry, which means ..

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Who is credited with the discovery of the element mercury?

Mercury is seldom found free in nature, which may be one reason its discovery cannot be traced to an individual. It is mostly found combined with sulfur in a material known as cinnabar. Mercury easily combines with a number of other elements.\n\nThe chemical symbol of mercury is Hg, which comes from the Greek word meaning "liquid silver." A more recent term for the element is quicksilver. Mercury is highly toxic as are some of its compounds. The element does have beneficial uses because it can easily form amalgams with various other metals. Various compounds containing mercury have been used f..

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Why isn't Pluto a planet any more?

The object that caused this change is called Eris. Like Eris, Pluto is now considered to be a dwarf planet. Pluto is also classified as a plutoid, which means that it's a dwarf planet that exists beyond the planet Neptune in space. The three known plutoids are Pluto, Eris and Makemake.\nThe three qualifications for an object to be considered a planet are that the object must orbit around the sun, it must be a sphere shape due to its own gravitational force and it must have cleared the neighborhood around its orbit. Because Pluto is only slightly larger than other objects in its orbit, it ..

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How do tornado sirens work?

Tornado sirens emit two separate tones. An up and down tone that lasts for three minutes signifies a weather emergency. A short tone that lasts for approximately 45 seconds signifies that all is clear and the warning has passed.\nWhen sirens are activated, it is a warning to the public that they should seek indoor shelter immediately and wait for the all clear signal. It is important for residents to watch the local news or listen to the radio for instructions and weather updates. If there is no power, it is important to listen for updates on a battery-operated radio.\nTornado sirens are typic..

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What are the advantages of the coelom in animals?

Prior to the development of a coelem, some animals relied on a solid layer of tissue between their exterior and gut as an anchor for movement. This meant that internal organs were embedded in solid material and could not move around to accommodate different positions. Many of these organisms also have incomplete digestive tracts, so that they must eat and release waste through the same opening. Many groups of animals developed what is known as a pseudocoelem, which includes a complete digestive tract and body cavity, granting many of the benefits of a true coelem.\nA true coelem, unlike a pseu..

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What are the symptoms of a bad MAF sensor?

One indication of a bad MAF sensor is that the engine may have trouble starting or turning over. A bad MAF sensor can also cause low gas mileage, engine stalling or jerking during acceleration. One of the most obvious indicators is the check engine light flashing, which happens after the problem has become significantly worse. However, since many problems that can cause this to happen, the car's computer must be analyzed to determine the actual problem.\nEither a mechanic can analyze the car's computer or the owner can do it with the purchase of a device that plugs directly into the ..

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What is the unit for frequency?

The clock rate of computer central processing units are measured in megahertz or gigahertz, which allow consumers to compare CPU performance. The transmission signals for Wi-Fi and Bluetooth networks are also measured in gigahertz; these network signals are generally in the ranges of 2.4 gigahertz or 5 gigahertz.\nRadians per second are used as a unit to measure angular frequency. These units are used to quantify rotational speed, and an angular frequency of 2? radians per second is equal to 1 hertz.

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